/**
 @file  peer.c
 @brief ENet peer management functions
*/
#include <string.h>
#define ENET_BUILDING_LIB 1
#include "enet.h"

/** @defgroup peer ENet peer functions
	@{
*/

/** Configures throttle parameter for a peer.

	Unreliable packets are dropped by ENet in response to the varying conditions
	of the Internet connection to the peer.  The throttle represents a probability
	that an unreliable packet should not be dropped and thus sent by ENet to the peer.
	The lowest mean round trip time from the sending of a reliable packet to the
	receipt of its acknowledgement is measured over an amount of time specified by
	the interval parameter in milliseconds.  If a measured round trip time happens to
	be significantly less than the mean round trip time measured over the interval,
	then the throttle probability is increased to allow more traffic by an amount
	specified in the acceleration parameter, which is a ratio to the ENET_PEER_PACKET_THROTTLE_SCALE
	constant.  If a measured round trip time happens to be significantly greater than
	the mean round trip time measured over the interval, then the throttle probability
	is decreased to limit traffic by an amount specified in the deceleration parameter, which
	is a ratio to the ENET_PEER_PACKET_THROTTLE_SCALE constant.  When the throttle has
	a value of ENET_PEER_PACKET_THROTTLE_SCALE, on unreliable packets are dropped by
	ENet, and so 100% of all unreliable packets will be sent.  When the throttle has a
	value of 0, all unreliable packets are dropped by ENet, and so 0% of all unreliable
	packets will be sent.  Intermediate values for the throttle represent intermediate
	probabilities between 0% and 100% of unreliable packets being sent.  The bandwidth
	limits of the local and foreign hosts are taken into account to determine a
	sensible limit for the throttle probability above which it should not raise even in
	the best of conditions.

	@param peer peer to configure
	@param interval interval, in milliseconds, over which to measure lowest mean RTT; the default value is ENET_PEER_PACKET_THROTTLE_INTERVAL.
	@param acceleration rate at which to increase the throttle probability as mean RTT declines
	@param deceleration rate at which to decrease the throttle probability as mean RTT increases
*/
void
enet_peer_throttle_configure(ENetPeer * peer, enet_uint32 interval, enet_uint32 acceleration, enet_uint32 deceleration)
{
	ENetProtocol command;

	peer->packetThrottleInterval = interval;
	peer->packetThrottleAcceleration = acceleration;
	peer->packetThrottleDeceleration = deceleration;

	command.header.command = ENET_PROTOCOL_COMMAND_THROTTLE_CONFIGURE | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
	command.header.channelID = 0xFF;

	command.throttleConfigure.packetThrottleInterval = ENET_HOST_TO_NET_32(interval);
	command.throttleConfigure.packetThrottleAcceleration = ENET_HOST_TO_NET_32(acceleration);
	command.throttleConfigure.packetThrottleDeceleration = ENET_HOST_TO_NET_32(deceleration);

	enet_peer_queue_outgoing_command(peer, &command, NULL, 0, 0);
}

int
enet_peer_throttle(ENetPeer * peer, enet_uint32 rtt)
{
	if (peer->lastRoundTripTime <= peer->lastRoundTripTimeVariance)
	{
		peer->packetThrottle = peer->packetThrottleLimit;
	}
	else
		if (rtt < peer->lastRoundTripTime)
		{
			peer->packetThrottle += peer->packetThrottleAcceleration;

			if (peer->packetThrottle > peer->packetThrottleLimit)
				peer->packetThrottle = peer->packetThrottleLimit;

			return 1;
		}
		else
			if (rtt > peer->lastRoundTripTime + 2 * peer->lastRoundTripTimeVariance)
			{
				if (peer->packetThrottle > peer->packetThrottleDeceleration)
					peer->packetThrottle -= peer->packetThrottleDeceleration;
				else
					peer->packetThrottle = 0;

				return -1;
			}

	return 0;
}

/** Queues a packet to be sent.
	@param peer destination for the packet
	@param channelID channel on which to send
	@param packet packet to send
	@retval 0 on success
	@retval < 0 on failure
*/
int
enet_peer_send(ENetPeer * peer, enet_uint8 channelID, ENetPacket * packet)
{
	ENetChannel * channel = &peer->channels[channelID];
	ENetProtocol command;
	size_t fragmentLength;

	if (peer->state != ENET_PEER_STATE_CONNECTED ||
		channelID >= peer->channelCount)
		return -1;

	fragmentLength = peer->mtu - sizeof(ENetProtocolHeader) - sizeof(ENetProtocolSendFragment);

	if (packet->dataLength > fragmentLength)
	{
		enet_uint16 startSequenceNumber = ENET_HOST_TO_NET_16(channel->outgoingReliableSequenceNumber + 1);
		enet_uint32 fragmentCount = ENET_HOST_TO_NET_32((packet->dataLength + fragmentLength - 1) / fragmentLength),
			fragmentNumber,
			fragmentOffset;
		ENetList fragments;
		ENetOutgoingCommand * fragment;

		enet_list_clear(&fragments);

		for (fragmentNumber = 0,
			fragmentOffset = 0;
			fragmentOffset < packet->dataLength;
			++fragmentNumber,
			fragmentOffset += fragmentLength)
		{
			if (packet->dataLength - fragmentOffset < fragmentLength)
				fragmentLength = packet->dataLength - fragmentOffset;

			fragment = (ENetOutgoingCommand *)enet_malloc(sizeof(ENetOutgoingCommand));
			if (fragment == NULL)
			{
				while (!enet_list_empty(&fragments))
				{
					fragment = (ENetOutgoingCommand *)enet_list_remove(enet_list_begin(&fragments));

					enet_free(fragment);
				}

				return -1;
			}

			fragment->fragmentOffset = fragmentOffset;
			fragment->fragmentLength = fragmentLength;
			fragment->packet = packet;
			fragment->command.header.command = ENET_PROTOCOL_COMMAND_SEND_FRAGMENT | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
			fragment->command.header.channelID = channelID;
			fragment->command.sendFragment.startSequenceNumber = startSequenceNumber;
			fragment->command.sendFragment.dataLength = ENET_HOST_TO_NET_16(fragmentLength);
			fragment->command.sendFragment.fragmentCount = fragmentCount;
			fragment->command.sendFragment.fragmentNumber = ENET_HOST_TO_NET_32(fragmentNumber);
			fragment->command.sendFragment.totalLength = ENET_HOST_TO_NET_32(packet->dataLength);
			fragment->command.sendFragment.fragmentOffset = ENET_NET_TO_HOST_32(fragmentOffset);

			enet_list_insert(enet_list_end(&fragments), fragment);
		}

		packet->referenceCount += fragmentNumber;

		while (!enet_list_empty(&fragments))
		{
			fragment = (ENetOutgoingCommand *)enet_list_remove(enet_list_begin(&fragments));

			enet_peer_setup_outgoing_command(peer, fragment);
		}

		return 0;
	}

	command.header.channelID = channelID;

	if (packet->flags & ENET_PACKET_FLAG_RELIABLE)
	{
		command.header.command = ENET_PROTOCOL_COMMAND_SEND_RELIABLE | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
		command.sendReliable.dataLength = ENET_HOST_TO_NET_16(packet->dataLength);
	}
	else
		if (packet->flags & ENET_PACKET_FLAG_UNSEQUENCED)
		{
			command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED | ENET_PROTOCOL_COMMAND_FLAG_UNSEQUENCED;
			command.sendUnsequenced.unsequencedGroup = ENET_HOST_TO_NET_16(peer->outgoingUnsequencedGroup + 1);
			command.sendUnsequenced.dataLength = ENET_HOST_TO_NET_16(packet->dataLength);
		}
		else
			if (channel->outgoingUnreliableSequenceNumber >= 0xFFFF)
			{
				command.header.command = ENET_PROTOCOL_COMMAND_SEND_RELIABLE | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
				command.sendReliable.dataLength = ENET_HOST_TO_NET_16(packet->dataLength);
			}
			else
			{
				command.header.command = ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE;
				command.sendUnreliable.unreliableSequenceNumber = ENET_HOST_TO_NET_16(channel->outgoingUnreliableSequenceNumber + 1);
				command.sendUnreliable.dataLength = ENET_HOST_TO_NET_16(packet->dataLength);
			}

	if (enet_peer_queue_outgoing_command(peer, &command, packet, 0, packet->dataLength) == NULL)
		return -1;

	return 0;
}

/** Attempts to dequeue any incoming queued packet.
	@param peer peer to dequeue packets from
	@param channelID holds the channel ID of the channel the packet was received on success
	@returns a pointer to the packet, or NULL if there are no available incoming queued packets
*/
ENetPacket *
enet_peer_receive(ENetPeer * peer, enet_uint8 * channelID)
{
	ENetIncomingCommand * incomingCommand;
	ENetPacket * packet;

	if (enet_list_empty(&peer->dispatchedCommands))
		return NULL;

	incomingCommand = (ENetIncomingCommand *)enet_list_remove(enet_list_begin(&peer->dispatchedCommands));

	if (channelID != NULL)
		* channelID = incomingCommand->command.header.channelID;

	packet = incomingCommand->packet;

	--packet->referenceCount;

	if (incomingCommand->fragments != NULL)
		enet_free(incomingCommand->fragments);

	enet_free(incomingCommand);

	return packet;
}

static void
enet_peer_reset_outgoing_commands(ENetList * queue)
{
	ENetOutgoingCommand * outgoingCommand;

	while (!enet_list_empty(queue))
	{
		outgoingCommand = (ENetOutgoingCommand *)enet_list_remove(enet_list_begin(queue));

		if (outgoingCommand->packet != NULL)
		{
			--outgoingCommand->packet->referenceCount;

			if (outgoingCommand->packet->referenceCount == 0)
				enet_packet_destroy(outgoingCommand->packet);
		}

		enet_free(outgoingCommand);
	}
}

static void
enet_peer_reset_incoming_commands(ENetList * queue)
{
	ENetIncomingCommand * incomingCommand;

	while (!enet_list_empty(queue))
	{
		incomingCommand = (ENetIncomingCommand *)enet_list_remove(enet_list_begin(queue));

		if (incomingCommand->packet != NULL)
		{
			--incomingCommand->packet->referenceCount;

			if (incomingCommand->packet->referenceCount == 0)
				enet_packet_destroy(incomingCommand->packet);
		}

		if (incomingCommand->fragments != NULL)
			enet_free(incomingCommand->fragments);

		enet_free(incomingCommand);
	}
}

void
enet_peer_reset_queues(ENetPeer * peer)
{
	ENetChannel * channel;

	if (peer->needsDispatch)
	{
		enet_list_remove(&peer->dispatchList);

		peer->needsDispatch = 0;
	}

	while (!enet_list_empty(&peer->acknowledgements))
		enet_free(enet_list_remove(enet_list_begin(&peer->acknowledgements)));

	enet_peer_reset_outgoing_commands(&peer->sentReliableCommands);
	enet_peer_reset_outgoing_commands(&peer->sentUnreliableCommands);
	enet_peer_reset_outgoing_commands(&peer->outgoingReliableCommands);
	enet_peer_reset_outgoing_commands(&peer->outgoingUnreliableCommands);
	enet_peer_reset_incoming_commands(&peer->dispatchedCommands);

	if (peer->channels != NULL && peer->channelCount > 0)
	{
		for (channel = peer->channels;
			channel < &peer->channels[peer->channelCount];
			++channel)
		{
			enet_peer_reset_incoming_commands(&channel->incomingReliableCommands);
			enet_peer_reset_incoming_commands(&channel->incomingUnreliableCommands);
		}

		enet_free(peer->channels);
	}

	peer->channels = NULL;
	peer->channelCount = 0;
}

/** Forcefully disconnects a peer.
	@param peer peer to forcefully disconnect
	@remarks The foreign host represented by the peer is not notified of the disconnection and will timeout
	on its connection to the local host.
*/
void
enet_peer_reset(ENetPeer * peer)
{
	peer->outgoingPeerID = ENET_PROTOCOL_MAXIMUM_PEER_ID;
	peer->sessionID = 0;

	peer->state = ENET_PEER_STATE_DISCONNECTED;

	peer->incomingBandwidth = 0;
	peer->outgoingBandwidth = 0;
	peer->incomingBandwidthThrottleEpoch = 0;
	peer->outgoingBandwidthThrottleEpoch = 0;
	peer->incomingDataTotal = 0;
	peer->outgoingDataTotal = 0;
	peer->lastSendTime = 0;
	peer->lastReceiveTime = 0;
	peer->nextTimeout = 0;
	peer->earliestTimeout = 0;
	peer->packetLossEpoch = 0;
	peer->packetsSent = 0;
	peer->packetsLost = 0;
	peer->packetLoss = 0;
	peer->packetLossVariance = 0;
	peer->packetThrottle = ENET_PEER_DEFAULT_PACKET_THROTTLE;
	peer->packetThrottleLimit = ENET_PEER_PACKET_THROTTLE_SCALE;
	peer->packetThrottleCounter = 0;
	peer->packetThrottleEpoch = 0;
	peer->packetThrottleAcceleration = ENET_PEER_PACKET_THROTTLE_ACCELERATION;
	peer->packetThrottleDeceleration = ENET_PEER_PACKET_THROTTLE_DECELERATION;
	peer->packetThrottleInterval = ENET_PEER_PACKET_THROTTLE_INTERVAL;
	peer->lastRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
	peer->lowestRoundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
	peer->lastRoundTripTimeVariance = 0;
	peer->highestRoundTripTimeVariance = 0;
	peer->roundTripTime = ENET_PEER_DEFAULT_ROUND_TRIP_TIME;
	peer->roundTripTimeVariance = 0;
	peer->mtu = peer->host->mtu;
	peer->reliableDataInTransit = 0;
	peer->outgoingReliableSequenceNumber = 0;
	peer->windowSize = ENET_PROTOCOL_MAXIMUM_WINDOW_SIZE;
	peer->incomingUnsequencedGroup = 0;
	peer->outgoingUnsequencedGroup = 0;
	peer->disconnectData = 0;

	memset(peer->unsequencedWindow, 0, sizeof(peer->unsequencedWindow));

	enet_peer_reset_queues(peer);
}

/** Sends a ping request to a peer.
	@param peer destination for the ping request
	@remarks ping requests factor into the mean round trip time as designated by the
	roundTripTime field in the ENetPeer structure.  Enet automatically pings all connected
	peers at regular intervals, however, this function may be called to ensure more
	frequent ping requests.
*/
void
enet_peer_ping(ENetPeer * peer)
{
	ENetProtocol command;

	if (peer->state != ENET_PEER_STATE_CONNECTED)
		return;

	command.header.command = ENET_PROTOCOL_COMMAND_PING | ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
	command.header.channelID = 0xFF;

	enet_peer_queue_outgoing_command(peer, &command, NULL, 0, 0);
}

/** Force an immediate disconnection from a peer.
	@param peer peer to disconnect
	@param data data describing the disconnection
	@remarks No ENET_EVENT_DISCONNECT event will be generated. The foreign peer is not
	guarenteed to receive the disconnect notification, and is reset immediately upon
	return from this function.
*/
void
enet_peer_disconnect_now(ENetPeer * peer, enet_uint32 data)
{
	ENetProtocol command;

	if (peer->state == ENET_PEER_STATE_DISCONNECTED)
		return;

	if (peer->state != ENET_PEER_STATE_ZOMBIE &&
		peer->state != ENET_PEER_STATE_DISCONNECTING)
	{
		enet_peer_reset_queues(peer);

		command.header.command = ENET_PROTOCOL_COMMAND_DISCONNECT | ENET_PROTOCOL_COMMAND_FLAG_UNSEQUENCED;
		command.header.channelID = 0xFF;
		command.disconnect.data = ENET_HOST_TO_NET_32(data);

		enet_peer_queue_outgoing_command(peer, &command, NULL, 0, 0);

		enet_host_flush(peer->host);
	}

	enet_peer_reset(peer);
}

/** Request a disconnection from a peer.
	@param peer peer to request a disconnection
	@param data data describing the disconnection
	@remarks An ENET_EVENT_DISCONNECT event will be generated by enet_host_service()
	once the disconnection is complete.
*/
void
enet_peer_disconnect(ENetPeer * peer, enet_uint32 data)
{
	ENetProtocol command;

	if (peer->state == ENET_PEER_STATE_DISCONNECTING ||
		peer->state == ENET_PEER_STATE_DISCONNECTED ||
		peer->state == ENET_PEER_STATE_ACKNOWLEDGING_DISCONNECT ||
		peer->state == ENET_PEER_STATE_ZOMBIE)
		return;

	enet_peer_reset_queues(peer);

	command.header.command = ENET_PROTOCOL_COMMAND_DISCONNECT;
	command.header.channelID = 0xFF;
	command.disconnect.data = ENET_HOST_TO_NET_32(data);

	if (peer->state == ENET_PEER_STATE_CONNECTED || peer->state == ENET_PEER_STATE_DISCONNECT_LATER)
		command.header.command |= ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE;
	else
		command.header.command |= ENET_PROTOCOL_COMMAND_FLAG_UNSEQUENCED;

	enet_peer_queue_outgoing_command(peer, &command, NULL, 0, 0);

	if (peer->state == ENET_PEER_STATE_CONNECTED || peer->state == ENET_PEER_STATE_DISCONNECT_LATER)
		peer->state = ENET_PEER_STATE_DISCONNECTING;
	else
	{
		enet_host_flush(peer->host);
		enet_peer_reset(peer);
	}
}

/** Request a disconnection from a peer, but only after all queued outgoing packets are sent.
	@param peer peer to request a disconnection
	@param data data describing the disconnection
	@remarks An ENET_EVENT_DISCONNECT event will be generated by enet_host_service()
	once the disconnection is complete.
*/
void
enet_peer_disconnect_later(ENetPeer * peer, enet_uint32 data)
{
	if ((peer->state == ENET_PEER_STATE_CONNECTED || peer->state == ENET_PEER_STATE_DISCONNECT_LATER) &&
		!(enet_list_empty(&peer->outgoingReliableCommands) &&
			enet_list_empty(&peer->outgoingUnreliableCommands) &&
			enet_list_empty(&peer->sentReliableCommands)))
	{
		peer->state = ENET_PEER_STATE_DISCONNECT_LATER;
		peer->disconnectData = data;
	}
	else
		enet_peer_disconnect(peer, data);
}

ENetAcknowledgement *
enet_peer_queue_acknowledgement(ENetPeer * peer, const ENetProtocol * command, enet_uint16 sentTime)
{
	ENetAcknowledgement * acknowledgement;

	if (command->header.channelID < peer->channelCount)
	{
		ENetChannel * channel = &peer->channels[command->header.channelID];
		enet_uint16 reliableWindow = command->header.reliableSequenceNumber / ENET_PEER_RELIABLE_WINDOW_SIZE,
			currentWindow = channel->incomingReliableSequenceNumber / ENET_PEER_RELIABLE_WINDOW_SIZE;

		if (command->header.reliableSequenceNumber < channel->incomingReliableSequenceNumber)
			reliableWindow += ENET_PEER_RELIABLE_WINDOWS;

		if (reliableWindow >= currentWindow + ENET_PEER_FREE_RELIABLE_WINDOWS - 1 && reliableWindow <= currentWindow + ENET_PEER_FREE_RELIABLE_WINDOWS)
			return NULL;
	}

	acknowledgement = (ENetAcknowledgement *)enet_malloc(sizeof(ENetAcknowledgement));
	if (acknowledgement == NULL)
		return NULL;

	peer->outgoingDataTotal += sizeof(ENetProtocolAcknowledge);

	acknowledgement->sentTime = sentTime;
	acknowledgement->command = *command;

	enet_list_insert(enet_list_end(&peer->acknowledgements), acknowledgement);

	return acknowledgement;
}

void
enet_peer_setup_outgoing_command(ENetPeer * peer, ENetOutgoingCommand * outgoingCommand)
{
	ENetChannel * channel = &peer->channels[outgoingCommand->command.header.channelID];

	peer->outgoingDataTotal += enet_protocol_command_size(outgoingCommand->command.header.command) + outgoingCommand->fragmentLength;

	if (outgoingCommand->command.header.channelID == 0xFF)
	{
		++peer->outgoingReliableSequenceNumber;

		outgoingCommand->reliableSequenceNumber = peer->outgoingReliableSequenceNumber;
		outgoingCommand->unreliableSequenceNumber = 0;
	}
	else
		if (outgoingCommand->command.header.command & ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE)
		{
			++channel->outgoingReliableSequenceNumber;
			channel->outgoingUnreliableSequenceNumber = 0;

			outgoingCommand->reliableSequenceNumber = channel->outgoingReliableSequenceNumber;
			outgoingCommand->unreliableSequenceNumber = 0;
		}
		else
			if (outgoingCommand->command.header.command & ENET_PROTOCOL_COMMAND_FLAG_UNSEQUENCED)
			{
				++peer->outgoingUnsequencedGroup;

				outgoingCommand->reliableSequenceNumber = 0;
				outgoingCommand->unreliableSequenceNumber = 0;
			}
			else
			{
				++channel->outgoingUnreliableSequenceNumber;

				outgoingCommand->reliableSequenceNumber = channel->outgoingReliableSequenceNumber;
				outgoingCommand->unreliableSequenceNumber = channel->outgoingUnreliableSequenceNumber;
			}

	outgoingCommand->sendAttempts = 0;
	outgoingCommand->sentTime = 0;
	outgoingCommand->roundTripTimeout = 0;
	outgoingCommand->roundTripTimeoutLimit = 0;
	outgoingCommand->command.header.reliableSequenceNumber = ENET_HOST_TO_NET_16(outgoingCommand->reliableSequenceNumber);

	if (outgoingCommand->command.header.command & ENET_PROTOCOL_COMMAND_FLAG_ACKNOWLEDGE)
		enet_list_insert(enet_list_end(&peer->outgoingReliableCommands), outgoingCommand);
	else
		enet_list_insert(enet_list_end(&peer->outgoingUnreliableCommands), outgoingCommand);
}

ENetOutgoingCommand *
enet_peer_queue_outgoing_command(ENetPeer * peer, const ENetProtocol * command, ENetPacket * packet, enet_uint32 offset, enet_uint16 length)
{
	ENetOutgoingCommand * outgoingCommand = (ENetOutgoingCommand *)enet_malloc(sizeof(ENetOutgoingCommand));
	if (outgoingCommand == NULL)
		return NULL;

	outgoingCommand->command = *command;
	outgoingCommand->fragmentOffset = offset;
	outgoingCommand->fragmentLength = length;
	outgoingCommand->packet = packet;
	if (packet != NULL)
		++packet->referenceCount;

	enet_peer_setup_outgoing_command(peer, outgoingCommand);

	return outgoingCommand;
}

void
enet_peer_dispatch_incoming_unreliable_commands(ENetPeer * peer, ENetChannel * channel)
{
	ENetListIterator currentCommand;

	for (currentCommand = enet_list_begin(&channel->incomingUnreliableCommands);
		currentCommand != enet_list_end(&channel->incomingUnreliableCommands);
		currentCommand = enet_list_next(currentCommand))
	{
		ENetIncomingCommand * incomingCommand = (ENetIncomingCommand *)currentCommand;

		if ((incomingCommand->command.header.command & ENET_PROTOCOL_COMMAND_MASK) == ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE)
		{
			if (incomingCommand->reliableSequenceNumber != channel->incomingReliableSequenceNumber)
				break;

			channel->incomingUnreliableSequenceNumber = incomingCommand->unreliableSequenceNumber;
		}
	}

	if (currentCommand == enet_list_begin(&channel->incomingUnreliableCommands))
		return;

	enet_list_move(enet_list_end(&peer->dispatchedCommands), enet_list_begin(&channel->incomingUnreliableCommands), enet_list_previous(currentCommand));

	if (!peer->needsDispatch)
	{
		enet_list_insert(enet_list_end(&peer->host->dispatchQueue), &peer->dispatchList);

		peer->needsDispatch = 1;
	}
}

void
enet_peer_dispatch_incoming_reliable_commands(ENetPeer * peer, ENetChannel * channel)
{
	ENetListIterator currentCommand;

	for (currentCommand = enet_list_begin(&channel->incomingReliableCommands);
		currentCommand != enet_list_end(&channel->incomingReliableCommands);
		currentCommand = enet_list_next(currentCommand))
	{
		ENetIncomingCommand * incomingCommand = (ENetIncomingCommand *)currentCommand;

		if (incomingCommand->fragmentsRemaining > 0 ||
			incomingCommand->reliableSequenceNumber != (enet_uint16)(channel->incomingReliableSequenceNumber + 1))
			break;

		channel->incomingReliableSequenceNumber = incomingCommand->reliableSequenceNumber;

		if (incomingCommand->fragmentCount > 0)
			channel->incomingReliableSequenceNumber += incomingCommand->fragmentCount - 1;
	}

	if (currentCommand == enet_list_begin(&channel->incomingReliableCommands))
		return;

	channel->incomingUnreliableSequenceNumber = 0;

	enet_list_move(enet_list_end(&peer->dispatchedCommands), enet_list_begin(&channel->incomingReliableCommands), enet_list_previous(currentCommand));

	if (!peer->needsDispatch)
	{
		enet_list_insert(enet_list_end(&peer->host->dispatchQueue), &peer->dispatchList);

		peer->needsDispatch = 1;
	}

	enet_peer_dispatch_incoming_unreliable_commands(peer, channel);
}

ENetIncomingCommand *
enet_peer_queue_incoming_command(ENetPeer * peer, const ENetProtocol * command, ENetPacket * packet, enet_uint32 fragmentCount)
{
	static ENetIncomingCommand dummyCommand;

	ENetChannel * channel = &peer->channels[command->header.channelID];
	enet_uint32 unreliableSequenceNumber = 0, reliableSequenceNumber;
	enet_uint16 reliableWindow, currentWindow;
	ENetIncomingCommand * incomingCommand;
	ENetListIterator currentCommand;

	if (peer->state == ENET_PEER_STATE_DISCONNECT_LATER)
		goto freePacket;

	if ((command->header.command & ENET_PROTOCOL_COMMAND_MASK) != ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED)
	{
		reliableSequenceNumber = command->header.reliableSequenceNumber;
		reliableWindow = reliableSequenceNumber / ENET_PEER_RELIABLE_WINDOW_SIZE;
		currentWindow = channel->incomingReliableSequenceNumber / ENET_PEER_RELIABLE_WINDOW_SIZE;

		if (reliableSequenceNumber < channel->incomingReliableSequenceNumber)
			reliableWindow += ENET_PEER_RELIABLE_WINDOWS;

		if (reliableWindow < currentWindow || reliableWindow >= currentWindow + ENET_PEER_FREE_RELIABLE_WINDOWS - 1)
			goto freePacket;
	}

	switch (command->header.command & ENET_PROTOCOL_COMMAND_MASK)
	{
	case ENET_PROTOCOL_COMMAND_SEND_FRAGMENT:
	case ENET_PROTOCOL_COMMAND_SEND_RELIABLE:
		if (reliableSequenceNumber == channel->incomingReliableSequenceNumber)
			goto freePacket;

		for (currentCommand = enet_list_previous(enet_list_end(&channel->incomingReliableCommands));
			currentCommand != enet_list_end(&channel->incomingReliableCommands);
			currentCommand = enet_list_previous(currentCommand))
		{
			incomingCommand = (ENetIncomingCommand *)currentCommand;

			if (reliableSequenceNumber >= channel->incomingReliableSequenceNumber)
			{
				if (incomingCommand->reliableSequenceNumber < channel->incomingReliableSequenceNumber)
					continue;
			}
			else
				if (incomingCommand->reliableSequenceNumber >= channel->incomingReliableSequenceNumber)
					break;

			if (incomingCommand->reliableSequenceNumber <= reliableSequenceNumber)
			{
				if (incomingCommand->reliableSequenceNumber < reliableSequenceNumber)
					break;

				goto freePacket;
			}
		}
		break;

	case ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE:
		unreliableSequenceNumber = ENET_NET_TO_HOST_16(command->sendUnreliable.unreliableSequenceNumber);

		if (reliableSequenceNumber == channel->incomingReliableSequenceNumber &&
			unreliableSequenceNumber <= channel->incomingUnreliableSequenceNumber)
			goto freePacket;

		for (currentCommand = enet_list_previous(enet_list_end(&channel->incomingUnreliableCommands));
			currentCommand != enet_list_end(&channel->incomingUnreliableCommands);
			currentCommand = enet_list_previous(currentCommand))
		{
			incomingCommand = (ENetIncomingCommand *)currentCommand;

			if ((incomingCommand->command.header.command & ENET_PROTOCOL_COMMAND_MASK) != ENET_PROTOCOL_COMMAND_SEND_UNRELIABLE)
				continue;

			if (reliableSequenceNumber >= channel->incomingReliableSequenceNumber)
			{
				if (incomingCommand->reliableSequenceNumber < channel->incomingReliableSequenceNumber)
					continue;
			}
			else
				if (incomingCommand->reliableSequenceNumber >= channel->incomingReliableSequenceNumber)
					break;

			if (incomingCommand->reliableSequenceNumber < reliableSequenceNumber)
				break;

			if (incomingCommand->reliableSequenceNumber > reliableSequenceNumber)
				continue;

			if (incomingCommand->unreliableSequenceNumber <= unreliableSequenceNumber)
			{
				if (incomingCommand->unreliableSequenceNumber < unreliableSequenceNumber)
					break;

				goto freePacket;
			}
		}
		break;

	case ENET_PROTOCOL_COMMAND_SEND_UNSEQUENCED:
		currentCommand = enet_list_end(&channel->incomingUnreliableCommands);
		break;

	default:
		goto freePacket;
	}

	incomingCommand = (ENetIncomingCommand *)enet_malloc(sizeof(ENetIncomingCommand));
	if (incomingCommand == NULL)
		goto notifyError;

	incomingCommand->reliableSequenceNumber = command->header.reliableSequenceNumber;
	incomingCommand->unreliableSequenceNumber = unreliableSequenceNumber & 0xFFFF;
	incomingCommand->command = *command;
	incomingCommand->fragmentCount = fragmentCount;
	incomingCommand->fragmentsRemaining = fragmentCount;
	incomingCommand->packet = packet;
	incomingCommand->fragments = NULL;

	if (fragmentCount > 0)
	{
		incomingCommand->fragments = (enet_uint32 *)enet_malloc((fragmentCount + 31) / 32 * sizeof(enet_uint32));
		if (incomingCommand->fragments == NULL)
		{
			enet_free(incomingCommand);

			goto notifyError;
		}
		memset(incomingCommand->fragments, 0, (fragmentCount + 31) / 32 * sizeof(enet_uint32));
	}

	if (packet != NULL)
		++packet->referenceCount;

	enet_list_insert(enet_list_next(currentCommand), incomingCommand);

	switch (command->header.command & ENET_PROTOCOL_COMMAND_MASK)
	{
	case ENET_PROTOCOL_COMMAND_SEND_FRAGMENT:
	case ENET_PROTOCOL_COMMAND_SEND_RELIABLE:
		enet_peer_dispatch_incoming_reliable_commands(peer, channel);
		break;

	default:
		enet_peer_dispatch_incoming_unreliable_commands(peer, channel);
		break;
	}

	return incomingCommand;

freePacket:
	if (fragmentCount > 0)
		goto notifyError;

	if (packet != NULL && packet->referenceCount == 0)
		enet_packet_destroy(packet);

	return &dummyCommand;

notifyError:
	if (packet != NULL && packet->referenceCount == 0)
		enet_packet_destroy(packet);

	return NULL;
}

/** @} */